Part of the Sentron family, this 50A single-pole molded case circuit breaker delivers robust thermal-magnetic protection for commercial and industrial electrical systems. It mounts into Siemens P1, P2, and P3 panelboards, providing a reliable bolt-on connection. Featuring a high 100kAIC rating at 120VAC and reverse feed capabilities, the NGB1B050B is HACR and HID rated for versatile load handling.
Which Siemens panelboards are compatible with the NGB1B050B circuit breaker?
This breaker is designed for use in Siemens P1, P2, and P3 panelboards. When installing in P2 or P3 panels, a specific branch mounting kit is required to connect the breaker to the panel bus.
What does the B suffix at the end of the NGB1B050B catalog number indicate?
The B suffix indicates that the circuit breaker is supplied with factory-installed load lugs as standard.
Can the NGB1B050B be used in reverse feed applications?
Yes. Because it features a non-interchangeable thermal-magnetic trip unit, it meets UL 489 requirements for reverse feed applications without requiring additional modifications.
Is this circuit breaker suitable for direct current (DC) systems?
Yes, the NGB1B050B is rated for DC applications and provides an interrupting capacity of 14kA at 125VDC.
What wire sizes and materials are accepted by the standard lugs on this breaker?
The factory-installed lugs accept 8 to 1/0 AWG copper (Cu) conductors or 8 to 2/0 AWG aluminum (Al) conductors.
Is the Siemens NGB1B050B HACR rated?
Yes, this breaker is HACR rated, making it suitable for use with heating, air conditioning, and refrigeration equipment that requires this specific listing.
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Shipping
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Parcel shipments with item value over $99 qualify for free economy shipping within the continental US. Please call to confirm special handling instructions. We do not charge a handling fee or require a minimum amount on any order. SuperBreakers does not ship on customer accounts.
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Reviews
Review summary
Customers rate this product 4.5 out of 5 based on 8 reviews.
Siemens NGB3B015B - 15A 3 Pole Molded Case Circuit Breaker
I recommend this product
Rated 5 out of 5 stars
9/16/26
480v breakers
The breakers work great
BP
Bland P.
Verified Buyer
Reviewing
Siemens NGB3B100 - 100A 3 Pole Molded Case Circuit Breaker
I do not recommend this product
Rated 1 out of 5 stars
7/22/26
NO LUGS!!
I ordered this breaker and it arrived with no lugs. It was advertised as new so we didn't open the box and check until the shutdown we needed it for. When we discovered the lugs were missing we sent an email requesting a set overnighted. We didn't get a response for a couple of days, at which point we had already ordered lugs from their competitor Simply Breakers. They asked for pictures and questioned weather we had ordered the correct breaker asking if we needed lugs on both sides. This is a panel breaker and their is only one configuration that I am aware of which is bolted to bus in panel and wires to the three lugs on the other side. I have never had to order lugs separately for this style of breaker. They asked for pictures of box and what was in it, of course at this point the breaker is already installed and the box is thrown away. I sent a receipt for the overnight lugs from Simply breakers and asked for whatever credit they could provide. I received crickets to date. I have never had a problem with an order in the past from super breakers, but they are to busy to even respond to my request so I will think twice before I order anything from them again. It will be my last option once all others have been exhausted. Use Simply Breakers they have better stock and service.
PF
Paul F.
Verified Buyer
Reviewing
Siemens NGB3B060B - 60A 3 Pole Molded Case Circuit Breaker
I recommend this product
Rated 5 out of 5 stars
6/24/26
Great service, quick shippin
Need I say more.I have used SB. When we need it and need it quickly Always have what I need.
BP
BJ P.
Verified Buyer
Reviewing
Siemens NGB3B020B - 20A 3 Pole Molded Case Circuit Breaker
I recommend this product
Rated 5 out of 5 stars
5/11/26
NGB3B020B
I recently purchased the NGB3B020B and I’m very satisfied with the quality and performance. The breaker feels solid and well-made, and installation was straightforward. It works exactly as expected and provides reliable protection for my electrical setup. Shipping was fast and the product arrived in excellent condition. I would definitely purchase from this seller again.
RS
Radovan S.
Verified Buyer
Reviewing
Siemens NGB3B050B - 50A 3 Pole Molded Case Circuit Breaker